<!-- 购物车 组件 -->
<template>
  <div class="shopcart">
    <!-- 购物车 -->
    <div class="content">
      <!-- 主要内容 -->
      <div class="main-content" @click="toggleList">
        <div class="left">
          <div class="logo-wrapper">
            <div class="logo" :class="{'logoLight': totalCount > 0}">
              <i class="icon-shopping_cart"></i>
            </div>
            <div class="totalCount" v-show="totalCount > 0">{{ totalCount }}</div>
          </div>

          <div class="price" :class="{'priceLight':totalCount > 0}">￥{{ totalPrice }}</div>
          <div class="desc">另需配送费 {{ deliveryPrice }} 元</div>
        </div>

        <div class="right" @click.stop="pay">
          <div class="pay" :class="{'payLight': this.totalPrice >= this.minPrice}">{{ payDesc }}</div>
        </div>
      </div>

      <!-- 飞行小球 -->
      <div class="ball-content">
        <div v-for="ball in balls">
          <transition name="drop"
                      @before-enter="beforeDrop"
                      @enter="dropping"
                      @after-enter="afterDrop">
            <div class="ball" v-show="ball.show">
              <div class="inner inner-hook"></div>
            </div>
          </transition>
        </div>
      </div>

      <!-- 购物车列表 -->
      <transition name="fold">
        <div class="shopcart-list" v-show="listShow">
          <div class="list-header">
            <h1 class="title">购物车</h1>
            <span class="empty" @click="empty">清空</span>
          </div>

          <div class="list-content" ref="listContentRef">
            <ul>
              <li class="food" v-for="food in selectFoods">
                <span class="name">{{ food.name }}</span>

                <div class="price">
                  <span>￥{{ food.price * food.count }}</span>
                </div>

                <div class="control">
                  <cart-control :food="food"></cart-control>
                </div>
              </li>
            </ul>
          </div>
        </div>
      </transition>
    </div>

    <!-- 模糊背景 -->
    <transition name="fade">
      <div class="background" @click="hideList" v-show="listShow"></div>
    </transition>
  </div>
</template>

<script>
  import CartControl from '@/components/base/cart-control/cart-control'
  import BScroll from 'better-scroll'
  import { MessageBox } from 'mint-ui'

  export default {
    components: {
      CartControl
    },
    data () {
      return {
        // 每个小球当前的状态
        balls: [
          { show: false },
          { show: false },
          { show: false },
          { show: false },
          { show: false },
          { show: false },
          { show: false },
          { show: false },
          { show: false },
          { show: false }
        ],
        // 已经下落的小球（show = true）
        dropBalls: [],
        // 购物车列表是否折叠
        listShow: false
      }
    },
    props: {
      // 加入购物车的商品
      selectFoods: {
        type: Array,
        default () {
          return []
        }
      },
      // 配送费
      deliveryPrice: {
        type: Number,
        default: 0
      },
      // 起送费
      minPrice: {
        type: Number,
        default: 0
      }
    },
    watch: {
      selectFoods () {
        if (this.scroll) {
          this.scroll.refresh()
        }
      }
    },
    methods: {
      // 点击 + 派发的事件
      // 取一个未下落的小球执行接下来的下落动作
      drop (el) {
        for (let i = 0; i < this.balls.length; i++) {
          let ball = this.balls[i]
          if (!ball.show) {
            ball.show = true
            ball.el = el
            this.dropBalls.push(ball)
            return
          }
        }
      },
      // 对 show = true 的小球设置动作
      beforeDrop (el) {
        let count = this.balls.length

        while (count--) {
          let ball = this.balls[count]
          if (ball.show) {
            let rect = ball.el.getBoundingClientRect()
            let x = rect.left - 32
            let y = -(window.innerHeight - rect.top - 22)

            el.style.display = ''
            el.style.webkitTransform = `translate3d(0,${y}px,0)`
            el.style.transform = `translate3d(0,${y}px,0)`

            let inner = el.getElementsByClassName('inner-hook')[0]
            inner.style.webkitTransform = `translate3d(${x}px,0,0)`
            inner.style.transform = `translate3d(${x}px,0,0)`
          }
        }
      },
      dropping (el, done) {
        /* eslint-disable no-unused-vars */
        let rf = el.offsetHeight // 重绘，否则小球不会消失
        this.$nextTick(() => {
          el.style.webkitTransform = 'translate3d(0,0,0)'
          el.style.transform = 'translate3d(0,0,0)'

          let inner = el.getElementsByClassName('inner-hook')[0]
          inner.style.webkitTransform = 'translate3d(0,0,0)'
          inner.style.transform = 'translate3d(0,0,0)'

          el.addEventListener('transitionend', done)
        })
      },
      // 动作做完就把该小球 show=false
      afterDrop (el) {
        let ball = this.dropBalls.shift()
        if (ball) {
          ball.show = false
          el.style.display = 'none'
        }
      },
      toggleList () {
        if (!this.totalCount) {
          return
        }

        this.listShow = !this.listShow

        // 初始化 better-scroll
        if (this.listShow) {
          // setTimeout
          this.$nextTick(() => {
            if (!this.scroll) {
              this.scroll = new BScroll(this.$refs.listContentRef, {
                click: true
              })
            } else {
              this.scroll.refresh()
            }
          }, 20)
        }
      },
      // 支付
      pay () {
        if (this.totalPrice < this.minPrice) {
          return
        }
        // mint UI
        MessageBox.confirm(`您共需支付 ${this.totalPrice} 元`, '结算')
      },
      // 清空
      empty () {
        this.selectFoods.forEach((food) => {
          food.count = 0
        })

        this.listShow = false
      },
      hideList () {
        this.listShow = false
      }
    },
    filters: {},
    computed: {
      // 所选商品总价
      totalPrice () {
        let total = 0
        this.selectFoods.forEach((food) => {
          total += food.price * food.count
        })
        return total
      },
      // 所选商品总数量
      totalCount () {
        let total = 0
        this.selectFoods.forEach((food) => {
          total += food.count
        })
        return total
      },
      // 20元起送 、 还差10元起送 、 去结算
      payDesc () {
        if (this.totalPrice === 0) {
          return `${this.minPrice}元起送`
        } else if (this.totalPrice < this.minPrice) {
          return `还差${this.minPrice - this.totalPrice}元起送`
        } else {
          return '去结算'
        }
      }
    },
    created () {},
    mounted () {},
    destroyed () {}
  }
</script>

<style lang="scss" scoped>
  @import '~@/assets/scss/const.scss';
  @import '~@/assets/scss/mixin.scss';

  .shopcart {
    .content {
      position: fixed;
      left: 0;
      bottom: 0;
      width: 100%;
      height: 48px;
      z-index: 50;
      .main-content {
        display: flex;
        width: 100%;
        height: 48px;
        font-size: 0;
        background-color: #141d27;
        .left {
          flex: 1;
          .logo-wrapper {
            display: inline-block;
            position: relative;
            top: -10px;
            box-sizing: border-box;
            margin: 0 12px;
            padding: 6px;
            width: 56px;
            height: 56px;
            border-radius: 50%;
            vertical-align: top;
            text-align: center;
            background-color: #141d27;
            .logo {
              width: 100%;
              height: 100%;
              border-radius: 50%;
              background-color: #2b343c;
              i {
                font-size: 24px;
                line-height: 44px;
                color: #80858a;
              }
            }
            .logoLight {
              background-color: #FFDA61;
              & i {
                color: #333;
              }
            }
            .totalCount {
              position: absolute;
              right: 0;
              top: 0;
              width: 24px;
              height: 16px;
              line-height: 16px;
              border-radius: 12px 12px;
              font-size: 9px;
              font-weight: 700;
              color: #fff;
              background-color: rgb(240, 20, 20);
              box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.4);
            }
          }
          .price {
            display: inline-block;
            box-sizing: border-box;
            margin-top: 12px;
            padding-right: 12px;
            vertical-align: top;
            font-size: 16px;
            line-height: 24px;
            font-weight: 700;
            color: rgba(255, 255, 255, 0.4);
            border-right: 1px solid rgba(255, 255, 255, 0.1);
            &.priceLight {
              color: #fff;
            }
          }
          .desc {
            display: inline-block;
            vertical-align: top;
            line-height: 24px;
            margin: 12px 0 0 12px;
            font-size: 10px;
            color: rgba(255, 255, 255, 0.4);
          }
        }
        .right {
          flex: 0 0 105px;
          width: 105px;
          text-align: center;
          .pay {
            height: 48px;
            line-height: 48px;
            font-size: 12px;
            font-weight: 700;
            color: rgba(255, 255, 255, 0.4);
            background-color: #2b333b;
            &.payLight {
              background-color: #FFDA61;
              color: #333;
            }
          }
        }
        // 适配 iPhone 5
        @media screen and (max-width: 320px) {
          .right {
            flex: 0 0 80px;
            width: 80px;
            text-align: center;
          }
        }
      }
      // 飞行小球
      .ball-content {
        .ball {
          position: fixed;
          left: 32px;
          bottom: 22px;
          z-index: 200;
          // http://cubic-bezier.com
          transition: all 0.4s cubic-bezier(0.49, -0.29, 0.75, 0.41);
        }
        .inner {
          width: 16px;
          height: 16px;
          border-radius: 50%;
          background-color: #FFD161;
          transition: all 0.4s linear;
        }
      }
      // 购物车列表
      .shopcart-list {
        position: absolute;
        top: 0;
        left: 0;
        z-index: -1;
        width: 100%;
        transform: translate3d(0, -100%, 0);
        &.fold-enter-active, &.fold-leave-active {
          transition: all 0.5s;
        }
        &.fold-enter, &.fold-leave-active {
          transform: translate3d(0, 0, 0);
        }
        .list-header {
          height: 40px;
          line-height: 40px;
          padding: 0 18px;
          background-color: #f3f5f7;
          border-bottom: 1px solid rgba(7, 17, 27, 0.1);
          .title {
            float: left;
            font-size: 14px;
            color: rgb(7, 17, 27);
          }
          .empty {
            float: right;
            font-size: 12px;
            color: rgb(0, 160, 220);
          }
        }
        .list-content {
          max-height: 217px;
          padding: 0 18px;
          background-color: #fff;
          overflow: hidden;
          .food {
            position: relative;
            padding: 12px 0;
            box-sizing: border-box;
            border-bottom: 1px solid rgba(7, 17, 27, 0.1);
            .name {
              line-height: 24px;
              font-size: 14px;
              color: rgb(7, 17, 27);
            }
            .price {
              position: absolute;
              right: 95px;
              bottom: 12px;
              line-height: 24px;
              font-size: 14px;
              font-weight: 700;
              color: rgb(240, 20, 20);
            }
            .control {
              position: absolute;
              right: 0;
              bottom: -5px;
            }
          }
        }
      }
    }
    // 模糊背景
    .background {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      z-index: 40;
      opacity: 1;
      backdrop-filter: blur(10px);
      background-color: rgba(7, 17, 27, 0.6);
      &.fold-enter-active, &.fold-leave-active {
        transition: all .5s;
      }
      &.fold-enter, &.fold-leave-active {
        opacity: 0;
        background: rgba(7, 17, 27, 0);
      }
    }
  }
</style>
